NRC’s Report on the Davis-Besse Shield Building Safety Demonstrates an Intrusive and In-Depth Review
by Moderator
The
NRC recently issued a report that documents how we reached the
conclusion the cracks discovered in the Davis-Besse shield building do
not compromise its ability to perform its safety function.
We’ve
previously written about the NRC’s exhaustive efforts to ensure the
cracks found in the shield building around the Davis-Besse nuclear power
plant’s containment structure are not compromising current safety. This
report clearly demonstrates the questioning attitude and the safety
focus of our inspectors as they monitored FirstEnergy’s activities to
analyze the shield building cracks and to conduct painstaking reviews of
the company’s operability analysis.
Upon
the discovery of the cracks, we formed a special technical review team
consisting of NRC Region III inspectors and headquarters specialists.
This team was tasked with ensuring a thorough and rigorous review, and
they rose to the challenge.
First,
the NRC inspectors monitored FirstEnergy’s testing of the shield
building cracks; they verified the quality of the tests; and made sure
that the extent of the testing was sufficient to evaluate the extent of
the cracking in the structure. As a result of the questions raised by
our team, the company performed additional tests so there was enough
data to reach a valid conclusion.
Then,
the NRC inspectors spent a number of weeks reviewing and questioning
FirstEnergy’s analysis of shield building safety. They continued to
challenge the company’s calculations, engineering assumptions and
conclusions. Some members of the NRC’s team made multiple trips to
Davis-Besse to make sure their questions and concerns were effectively
addressed in face-to-face meetings with the site’s engineers and
consultants.
Two
revisions of FirstEnergy’s operability evaluation were needed before
our technical team was satisfied that it was thorough enough to show
that the shield building was safe for continued operation.
Our
work continues with the review of FirstEnergy’s root cause report and
proposed long-term corrective actions. We plan to finish the review,
issue the inspection report and schedule a public meeting during the
summer.
The NRC’s operability report can
be accessed on the NRC website. Background information on the discovery
of the shield building cracks in October 2011 and the NRC’s response to
the issue can be found in the following blog posts:
Viktoria Mitlyng
Public Affairs Officer
Region III
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